Electrical connector positioned in a battery pack

ABSTRACT

Electrical connectors for electrically connecting individual portable electrical energy storage cells making up a plurality of portable electrical energy storage cells that are part of a portable electrical energy storage device for powering portable devices such as vehicles or consumer electronics include bands of reduced cross-sectional area. The electrical connectors include conductive bands that promote reliable attachment between the electrical connector and portable electrical energy storage cells and provide the ability to electrically isolate failing or damaged cells.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.15/151,188, filed May 10, 2016 which claims priority to and the benefitof U.S. Provisional Application No. 62/159,594, filed May 11, 2015,which are hereby incorporated by reference in their entireties.

BACKGROUND Technical Field

The embodiments described herein relate to electrical connectionsbetween portable electrical energy storage cells making up a portableelectrical energy storage device, for example, portable electricalenergy storage devices used in electric powered devices such as vehiclesand consumer electronics.

Description of the Related Art

Batteries such as lithium-ion batteries are known for packing moreenergy into smaller, lighter units. Lithium-ion batteries have foundwide application in powering portable electronic devices such as cellphones, tablets, laptops, power tools and other high-current equipment.Their low weight and high energy density also makes lithium-ionbatteries attractive for use in hybrid vehicles and fullyelectric-powered vehicles.

A potential shortcoming of lithium-ion batteries is their electrolytesolutions. Unlike other types of batteries, in which the electrolytesconsist of aqueous solutions of acid or base, the electrolyte inlithium-ion cells typically consists of lithium salts in organicsolvents such as ethylene carbonate and ethyl methyl carbonate (whichcan be flammable).

Under normal operation, charging a lithium-ion battery causes lithiumions in the electrolyte solution to migrate from the cathode through athin porous polymer separator and insert themselves in the anode. Chargebalancing electrons also move to the anode but travel through anexternal circuit in the charger. Upon discharge, the reverse processoccurs, and electrons flow through the device being powered.

In very rare circumstances, internal or external short-circuiting of alithium-ion battery can occur. For example, the electric-powered devicecontaining the lithium-ion battery can undergo a severe impact or shockresulting in a breach in the battery, which could result in a shortcircuit. Due to the thin nature of the polymer separator,micrometer-sized metal particles generated during cutting, pressing,grinding, or other battery manufacturing steps can be present or findtheir way into the battery cell. These small metal particles canaccumulate and eventually form a short circuit between the anode and thecathode. Such short circuits are to be avoided because they can resultin temperatures at which the cathode may react with and decompose theelectrolyte solution, generating heat and reactive gases such ashydrocarbons. Typically, at normal operating temperatures, lithium-ionbatteries are very stable; however, above a certain temperaturelithium-ion battery stability becomes less predictable, and at anelevated temperature chemical reactions within the battery case willproduce gases resulting in an increase in the internal pressure withinthe battery case. These gases can react further with the cathode,liberating more heat and producing temperatures within or adjacent tothe battery that can ignite the electrolyte in the presence of oxygen.When the electrolyte burns, small amounts of oxygen are produced, whichmay help fuel the combustion. At some point, build-up of pressure withinthe battery case results in the battery case rupturing. The escaping gasmay ignite and combust. Some battery manufacturers design their cells sothat, in the unlikely event a cell ruptures and ignites, gases thatsupport combustion exit the cell in predetermined locations anddirections. For example, battery cells in the shape of conventional AAAor AA cells may be designed to vent from the terminal ends located ateach end of the cell.

In applications where only a single lithium-ion battery is utilized,failure of a battery and the potential for combustion creates anundesirable situation. The severity of this situation is increased whena plurality of lithium-ion batteries are deployed in the form of abattery bank or module. The combustion occurring when one lithium-ionbattery fails may produce local temperatures above the temperature atwhich other lithium-ion batteries are normally stable, causing theseother batteries to fail, rupture, and vent gases which then ignite andcombust. Thus, it is possible for the rupture of a single cell in a bankof lithium-ion cells to cause other cells in the bank to rupture anddischarge gases which ignite and burn. Fortunately, lithium-ionbatteries have proven to be very safe, and the failure and consequentrupture of a lithium-ion battery is a very rare event. Nonetheless,efforts have been made to reduce the risk of rupture and ignition ofgases exiting a ruptured lithium-ion battery. For example, developmentof materials used for cathodes has produced lithium-based cathodematerials that tolerate heat better than cathodes made from the widelyused lithium cobalt oxide. While these more recently developed materialsmay be more heat tolerant, this benefit comes at a price. For example,lithium manganese oxide cathodes have a lower charge capacity thanlithium cobalt oxide and still decompose at high temperatures. Lithiumiron phosphate cathodes stand up especially well to thermal abuse;however, their operating voltage and energy density on a volume basisare lower than those of lithium cobalt oxide cathodes.

Other efforts have focused on the polymer separator and its design. Forexample, it has been proposed to utilize a polymer separator thatsandwiches a layer of polyethylene between two layers of polypropylenein an effort to provide a degree of protection against mild overheating.As the temperature of the cell begins to approach that at which thestability of the cell becomes unpredictable, the polyethylene melts andplugs the pores in the polypropylene. When the pores of a polypropyleneare plugged by the polyethylene, lithium diffusion is blocked,effectively shutting the cell down before it has a chance to ignite.Other efforts have focused on utilizing polymer separators havingmelting points higher than polypropylene. For example, separators madefrom polyim ides and separators made from high molecular weightpolyethylene and an embedded ceramic layer have been proposed to form arobust higher melting point polymer separator. Formulating and utilizingless flammable electrolytes and nonvolatile, nonflammable ionic liquids,fluoroethers, and other highly fluorinated solvents as batteryelectrolytes have also been investigated. Researchers have developedlithium-ion batteries that contain no liquids at all. These solid-statebatteries contain inorganic lithium-ion conductors, which are inherentlynonflammable and are thus very stable, safe, and exhibit long cycle lifeand shelf life. However, the manufacture of these solid-state batteriesrequires costly, labor-intensive vacuum deposition methods.

When a portable electrical energy storage device includes a plurality ofportable electrical energy storage cells, some of the portableelectrical energy storage cells are typically electrically connected toeach other. One way to achieve such electrical connection is to attachan electrically conductive member to the terminals of the targetportable electrical energy storage cells. In the rare event a portableelectrical energy storage cell begins to fail, electric energy flowingto the failing portable electrical energy storage cell from stableportable electrical energy storage cells connected to the sameelectrically conductive member may promote generation of thermal energyat the failing cell. It is also possible that electrical energy flowingfrom the failing portable electrical energy storage cell to other stableportable electrical energy storage cells connected to the conductivemember may cause the temperature of the stable portable electricalenergy storage cells to rise. In both cases, the temperature of thefailing or stable electrical energy storage cells can increase to levelswhere cell stability is less predictable and/or alteration of damage tocomponents of a portable electrical energy storage cell may occur. Anunstable or damaged cell may burst or self-ignite.

While thermal fusing, e.g., spot welding, is an effective process toattach electrically conductive members to terminals of portableelectrical energy storage cells, such process is not without itschallenges. For example, the small size of the conductive members to bewelded to terminals of portable electrical energy storage cells make itchallenging to reliably contact the conductive members with theterminals of the portable electrical energy storage cells.

Despite efforts to avoid failure or damage to portable electrical energystorage cells, there continues to be a need to reduce exposure ofelectrical energy storage cells to temperatures which make the cells'stability less predictable and achieves solid and reliable contactbetween conductive members that are to be thermally fused to terminalsof portable electrical energy storage cells.

BRIEF SUMMARY

Embodiments described in this application relate to electricalconnectors for electrically connecting portable electrical energystorage cells making up a portable electrical energy storage device,methods of making such electrical connectors and methods for attachingelectrical connectors to a portable electrical energy storage cell.Electrical connectors in accordance with embodiments described in thisapplication include features that help protect a failing portableelectrical energy storage cell from further damage resulting fromelectric current flowing to the failing cell from other portableelectrical energy storage cells connected to the same electricalconnector as the failing cell. Electrical connectors in accordance withembodiments described in this application include features that helpprotect non-failing portable electrical energy storage cells from damageresulting from electric current flowing from a failing portableelectrical energy storage cell to the non-failing portable electricalenergy storage cell connected to the same electrical connector as thefailing portable electrical energy storage cell.

In embodiments of one described aspect, electrical connectors forelectrical connection to each of a plurality of portable electricalenergy storage cells making up a portable electrical energy storagedevice are described. The electrical connector includes an electricallyconductive frame and a plurality of integral electrically conductivetabs. Each of the plurality of integral electrically conductive tabs isin electrical communication with the electrically conductive frame. Theelectrical connector also includes a plurality of integral electricallyconductive supports with one integral electrically conductive support ofthe plurality of electrically conductive supports extending between oneof the plurality of integral electrically conductive tabs and theelectrically conductive frame. In accordance with embodiments describedin the application, the integral electrically conductive support extendsbetween one of the plurality of integral electrically conductive tabsand the electrically conductive frame and includes at least oneelectrically conductive band. The at least one electrically conductiveband having a cross-sectional area less than a cross-sectional area ofanother portion of the integral electrically conductive supportextending from one of the integral electrically conductive tabs.

In embodiments of another described aspect, the integral electricallyconductive support includes an upper surface and a lower surface and anopening extending from the upper surface to the lower surface.

In other embodiments, the integral electrically conductive supportincludes a first edge and a second edge with a first electricallyconductive band between the first edge and the opening and a secondelectrically conductive band between the second edge and the opening.

In yet another embodiment, the integral electrically conductive supportextending between the integral electrically conductive tab and theelectrically conductive frame includes two electrically conductivebands, each of the two electrically conductive bands having across-sectional area less than a cross-sectional area of another otherportion of the integral electrically conductive support extending fromone of the integral electrically conductive tabs.

In embodiments of another described aspect, the cross-sectional area ofone of the two electrically conductive bands is less than thecross-sectional area of the other one of the two electrically conductivebands.

In embodiments of another described aspect, methods of manufacturing anelectrical connector for electrical connection to each of a plurality ofportable electrical energy storage cells making up a portable electricalenergy storage device are described. The methods include providing anelectrically conductive substrate and forming a plurality of integralelectrically conductive tabs and a plurality of integral electricallyconductive supports in the electrically conductive substrate. Inaccordance with the described methods, one of the plurality of integralelectrically conductive supports extends from one of the integralelectrically conductive tabs and an electrically conductive band isformed in the electrically conductive support extending from the one ofthe integral electrically conductive tabs. The electrically conductiveband has a cross-sectional area less than a cross-sectional area ofanother portion of the integral electrically conductive supportextending from one of the integral electrically conductive tabs.

In embodiments of another described aspect, the plurality of integralelectrically conductive tabs are formed by displacing the integralelectrically conductive tab so it lies in a plane different from theplane in which the balance of the electrically conductive substratelies.

In other embodiments, forming an electrically conductive band includesforming two electrically conductive bands in the integral electricallyconductive support extending from one of the plurality of integralelectrically conductive tabs. Each of the two electrically conductivebands has a cross-sectional area less than a cross-sectional area ofanother portion of the integral electrically conductive supportextending from one of the integral electrically conductive tabs.

In yet other embodiments, described methods include forming anelectrically conductive band in one of the plurality of electricallyconductive supports extending from one of the integral conductive tabsby removing a portion of the integral electrically conductive supportextending from one of the plurality of integral electrically conductivetabs.

In further embodiments, the cross-sectional area of one of the twoelectrically conductive bands is less than the cross-sectional area ofthe other one of the two electrically conductive bands.

Embodiments of aspects described herein include methods of attaching anelectrical connector to a portable electrical energy storage cell of aportable electrical energy storage device. The described methods providea plurality of integral electrically conductive tabs and a plurality ofintegral electrically conductive support, where one of the plurality ofintegral electrically conductive supports extends from one of theintegral electrically conductive tabs and includes at least oneelectrically conductive band having a cross-sectional area less than across-sectional area of another portion of the integral electricallyconductive support extending from one of the integral electricallyconductive tabs. In accordance with these and other embodiments, oneintegral electrically conductive tab from which the one integralelectrically conductive support extends is heated and the one integralelectrically conductive tab from which the one integral electricallyconductive support extends is thermally fused to the portable electricalenergy storage cell.

In yet other embodiments of aspects described herein, the integralelectrically conductive support extending from one of the integralelectrically conductive tabs includes at least two electricallyconductive bands, with each of the two electrically conductive bandshaving a cross-sectional area less than a cross-sectional area of theother portion of the integral electrically conductive support. Incertain embodiments, the cross-sectional area of one of the at least twoelectrically conductive bands is less than the cross-sectional area ofanother of the at least two electrically conductive bands.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

In the drawings, identical reference numbers identify similar elementsor acts. The sizes and relative positions of elements in the drawingsare not necessarily drawn to scale. For example, the shapes of variouselements and angles are not drawn to scale, and some of these elementsare arbitrarily enlarged and positioned to improve drawing legibility.Further, the particular shapes of the elements as drawn, are notintended to convey any information regarding the actual shape of theparticular elements, and have been solely selected for ease ofrecognition in the drawings.

FIG. 1 is an isometric view of an electrical connector for connection toportable electrical energy storage cells of a portable electrical energystorage device, according to one non-limiting illustrated embodiment.

FIG. 2 is an top plan view of the electrical connector of FIG. 1.

FIG. 3 is a side elevation view of the electrical connector of FIG. 1.

FIG. 4 is a cross-section taken along line 4-4 in FIG. 2.

FIG. 5 is a cross-section taken along line 5-5 in FIG. 2.

DETAILED DESCRIPTION

It will be appreciated that, although specific embodiments of thesubject matter of this application have been described herein forpurposes of illustration, various modifications may be made withoutdeparting from the spirit and scope of the disclosed subject matter.Accordingly, the subject matter of this application is not limitedexcept as by the appended claims.

In the following description, certain specific details are set forth inorder to provide a thorough understanding of various disclosedembodiments. However, one skilled in the relevant art will recognizethat embodiments may be practiced without one or more of these specificdetails, or with other methods, components, materials, etc. In otherinstances, well-known structures associated with portable electricalenergy storage cells, e.g., batteries, have not been shown or describedin detail to avoid unnecessarily obscuring descriptions of theembodiments.

Unless the context requires otherwise, throughout the specification andclaims which follow, the word “comprise” and variations thereof, suchas, “comprises” and “comprising” are to be construed in an open,inclusive sense that is as “including, but not limited to.”

Reference throughout this specification to “one embodiment” or “anembodiment” means that a particular feature, structure or characteristicdescribed in connection with the embodiment is included in at least oneembodiment. Thus, the appearances of the phrases “in one embodiment” or“in an embodiment” in various places throughout this specification arenot necessarily all referring to the same embodiment.

The use of ordinals such as first, second and third does not necessarilyimply a ranked sense of order, but rather may only distinguish betweenmultiple instances of an act or structure.

Reference to portable electrical power storage device or electricalenergy storage device means any device capable of storing electricalpower and releasing stored electrical power including, but not limitedto, batteries, supercapacitors or ultracapacitors, and modules made upof a plurality of the same. Reference to portable electrical energystorage cell(s) means a chemical storage cell or cells, for instance,rechargeable or secondary battery cells including, but not limited to,nickel-cadmium alloy battery cells or lithium-ion battery cells. Anon-limiting example of portable electrical energy storage cells isillustrated in the figures as being cylindrical, e.g., similar in sizeand shape to conventional AAA size batteries; however, the presentdisclosure is not limited to this illustrated form factor.

The headings and Abstract of the Disclosure provided herein are forconvenience only and do not interpret the scope or meaning of theembodiments.

Generally described, the present disclosure is directed to examples ofportable electrical energy storage devices suitable to power electricdevices such as electric powered or hybrid type vehicles, e.g.,motorcycles, scooters and electric bicycles, electric powered tools,electric powered lawn and garden equipment, and the like, which includeone or more electrical connector for making an electrically conductiveconnection between a plurality of electrical energy storage cells makingup the electrical energy storage device. The present disclosure alsodescribes examples of methods of making such electrical connectors andmethods of attaching such electrical connectors to portable electricalenergy storage cells. Further description of portable electrical energystorage devices and electrical connectors in accordance with embodimentsdescribed herein is provided in the context of portable electricalenergy storage devices used with electric scooters; however, it shouldbe understood that portable electrical energy storage devices inaccordance with embodiments described herein are not limited toapplications in electric scooters. In addition, portable electricalenergy storage devices are described below with reference to a singleelectrical energy storage cell module containing a plurality ofelectrical energy storage cells. The present description is not limitedto electrical energy storage devices that include only a singleelectrical energy storage cell module and encompasses portableelectrical energy storage devices that include more than a singleelectrical energy storage cell module.

Referring to FIG. 1, an exemplary electrical connector 100 formed inaccordance with embodiments described herein is an electricallyconductive member that includes a plurality of integral electricallyconductive tabs 102, each for attachment to a terminal 103 of arespective portable electrical energy storage cell 104 illustrated inbroken lines. Though not illustrated, in exemplary embodiments, portableelectrical energy storage cells 104 comprise an array or module ofportable electrical energy storage cells making up a portion of aportable electrical energy storage device for powering an electricallypowered device, such as an electric vehicle. Electrical connector 100includes a plurality of integral electrically conductive supports106A-106H. One of the plurality of integral electrically conductivesupports 106A-106H extends between one of the respective plurality ofintegral electrically conductive tabs 102A-102H and an electricallyconductive frame 108 of electrical connector 100. Integral electricallyconductive supports 106A-106H provide electrical communication (i.e., anelectrical connection) between integral electrically conductive tabs102A-102H and electrically conductive frame 108. In the exemplaryembodiment illustrated in FIG. 1, the shape of some of the individualelectrically conductive supports 106A-106H differs. It should beunderstood that the shape of individual electrically conductive supportsin accordance with embodiments of an electrical connector describedherein can vary from those illustrated in FIG. 1. For example, the shapeof all of the individual electrically conductive supports can be thesame or the shape of every individual electrically conductive support inaccordance with embodiments described herein can be different.

Electrical connector 100 is formed from an electrically conductivematerial, e.g., a metal or metal alloy. Exemplary metals or metal alloysinclude nickel and nickel alloys; however, the described embodiments arenot limited to nickel and nickel alloys and include other conductivematerials that can be thermally fused to terminals of portableelectrical energy storage cells. Referring additionally to FIG. 3, inthe illustrated exemplary embodiment, electrically conductive frame 108as used herein refers to the portion of electrical connector 100 thatsubstantially defines a plane 109 schematically identified by line 110in FIG. 3. As seen in FIG. 3, integral electrically conductive tabs102A-102H lie in a second plane 112 schematically identified by line114. In FIGS. 1 and 3, plane 109 is spaced apart from and is above plane112. Integral electrically conductive supports 106A-106H extend betweenrespective integral electrically conductive tabs 102A-102H andelectrically conductive frame 108 and comprise portions of theelectrical connector 100 that do not lie substantially in plane 109 orplane 112.

An exemplary shape of integral electrically conductive pads 102A-102Hare shown in FIGS. 1-4; however, it is understood that integralelectrically conductive pads 102A-102H can be different in shape thanillustrated in FIGS. 1-4. For example, integral electrically conductivepads 102A-102H can be square, rectangular, triangular, oval and otherpolygonal and non-polygonal shapes.

The following description of features of integral electricallyconductive supports 106A-106H is provided with reference to onlyintegral electrically conductive support 106A; however, the descriptionis equally applicable to each electrically conductive support 106A-106H.As illustrated in FIGS. 1, 3 and 4, integral electrically conductivesupports 106A-106H extend from plane 109 (in which electricallyconductive frame 108 lies) downward to plane 112 (in which integralelectrically conductive tabs 102A-102H lie). Integral electricallyconductive support 106A is formed from an electrically conductivematerial such as those described above with reference to electricalconnector 100. Integral electrically conductive support 106A includes asection having a width that is constant along the length of conductivesupport 106A. For example, in FIG. 2, electrically conductive support106A has a width that is constant between the contour lines and slightlybeyond. Integral electrically conductive support 106A includes at leasta first electrically conductive band 116 and a second electricallyconductive band 118. Though integral electrically conductive support106A is illustrated as including two electrically conductive bands 116,118, it should be understood that integral electrically conductivesupport 106A could include fewer or more electrically conductive bands.For example, integral electrically conductive support 106A may includeonly one electrically conductive band or it may include more than twoelectrically conductive bands. When electrically conductive support 106Aincludes only one conductive band, conductive support 106A is able torotate more freely along the longitudinal axis of the band compared towhen conductive support 106A includes more than one band. Rotation ofconductive support 106A in this manner may cause conductive tab 102A totilt in a way that results in a smaller portion of conductive tab 102Abeing in direct contact with the terminal of an underlying portableelectrical energy storage cell. When the size of the area of contactbetween conductive tab 102A and the terminal of an underlying portableelectrical energy storage cell is reduced, the size of the areaavailable to thermally fuse tab 102A to the terminal of the underlyingcell is reduced, making it more difficult to achieve a reliableattachment. When conductive support 106A includes two or moreelectrically conductive bands, conductive support 106A is constrained atmore points compared to when only conductive band is present, thusreducing the ease with which conductive support 106A may be rotatedalong a longitudinal axis of the bands. Constraining the ease with whichconductive support 106A can be rotated reduces the degree to whichconductive tab 102A might be tilted out of a parallel relationship withthe upper surface of the terminal of an underlying portable electricalenergy storage cell. By reducing the degree to which conductive tab 102Amight be tilted out of parallel relationship with the upper surface ofthe terminal of an underlying portable electrical energy storage cell, areduction in the area available for thermal fusion is reduced, making iteasier to achieve a reliable attachment. With increasing numbers ofconductive bands, rotational freedom of conductive support 106Adiminishes.

In the embodiment illustrated in FIGS. 1-4, integral electricallyconductive support 106A includes an opening 120 passing through integralelectrically conductive support 106A from an upper surface 121 to alower surface 122. First electrically conductive band 116 extendsbetween an edge 123 of integral electrically conductive support 106A andopening 120. Edge 123 is an outer edge located opposite correspondingopening 120. Second electrically conductive band 118 extends betweenanother edge 125 of integral electrically conductive support 106A andopening 120. Edge 125 is an outer edge located opposite correspondingopening 120. Opening 120 is illustrated as an oval; however, it shouldbe understood that opening 120 may have a different shape such as apolygon or other non-polygon shape and is not limited to an oval shape.In addition, the location of opening 120 within integral electricallyconductive support 106A is not limited to the location illustrated inthe figures. For example, opening 120 can be positioned within integralelectrically conductive support 106A closer to electrically conductivetab 102A or further away from electrically conductive tab 102A.

In some embodiments, opening 120 is provided within a respective one ofintegral electrically conductive supports 106A-106H and extends betweencorresponding bands 116 and 118. A distance between outer edges of thebands 116 and 118 is substantially equal to a width of portions of therespective one of integral electrically conductive supports 106A-106Hthrough which opening 120 does not pass. In some embodiments, opening120 is formed within a respective one of integral electricallyconductive supports 106A-106H and extends between corresponding bands116 and 118. In these embodiments, a distance between outer edges of thebands 116 and 118 is less than a width of portions of the respective oneof integral electrically conductive supports 106A-106H through whichopening 120 does not pass. In some embodiments, an opening 120 is formedwithin a respective one of integral electrically conductive supports106A-106H and extends between corresponding bands 116 and 118. In theseembodiments, a distance between outer edges of the bands 116 and 118 isgreater than a width of portions of the respective one of integralelectrically conductive supports 106A-106H through which opening 120does not pass.

Referring to FIG. 5, first electrically conductive band 116 has across-sectional area that is less than the cross-sectional area of otherportions of integral electrically conductive support 106A. The portionsof integral electrically conductive support 106A having a largercross-section area than first electrically conductive band 116 includeportions 124A, 124B, 124C in FIGS. 1 and 2. Portions 124A, 124B, 124Care portions of integral electrically conductive support 106A thoughwhich opening 120 does not pass. In a similar fashion, secondelectrically conductive band 118 has a cross-sectional area that is lessthan the cross-sectional area of another portion of integralelectrically conductive support 106A. The cross-sectional area of bands116 and 118 are illustrated as being equal; however, embodimentsdescribed herein are not limited to bands having equal cross-sectionalareas. For example, one conductive band may have a cross-sectional areathat is less than other conductive bands making up a portion of theconductive support. The conductive band having a smaller cross-sectionalarea will more readily melt or “fry” (compared to the band having alarger cross-sectional area) when an electrical current above athreshold amount flows through the band. The melting or frying of theconductive band electrically isolates the portable electrical energystorage cell to which the conductive band is connected by a respectiveconductive tab.

Band 116 and/or band 118 included in electrical connectors formed inaccordance with embodiments described herein are able to electricallyisolate a portable electrical energy cell from other portable electricalenergy storage cells attached to the same connector when electriccurrent flowing through the band(s) exceed a threshold level. Forexample, in the event an individual portable electrical energy storagecell connected to the electrical connector fails, current from otherportable electrical energy storage cells connected to the sameelectrical connector may flow to the failed cell through the electricalconnector. In accordance with embodiments described herein, bands 116,118 support this current flow until such time the current becomes solarge it exceeds the threshold level and the band(s) cannot support thecurrent. When this occurs, the band(s) fail (e.g., melt or “fry”)causing a break in the electrical current path to the failed or failingportable electrical energy storage cell. This break in electricalcurrent path prevents current from portable electrical energy cellswhich have not failed from further damaging the failed or failingportable electrical energy storage cell. The break also preventselectrical energy released from the failed or failing portableelectrical energy storage cell from flowing to and damaging otherportable electrical energy storage cells connected to the sameelectrical connector as the failed or failing cell.

The cross-sectional area of bands 116, 118 should be large enough thatthe bands support a minimum amount of electrical current required undernormal operating conditions of the device being powered by the portableelectrical energy device, including high load conditions. On the otherhand, the cross-sectional area of bands 116, 118 should not be so largethat the band(s) do not melt or fry when current levels above athreshold level begin to flow through the bands. An exemplary thresholdlevel of current would be an amount of current greater than the amountof current that would flow under normal operating conditions of thedevice powered by the portable electrical energy storage device withoutthe presence of any failed or failing electrical energy storage cellsconnected to the electrical connector. For example, a threshold level ofcurrent would be an amount of electric current (greater than theelectrical current that flows through the bands under normal operationconditions) that flows to a failed or failing electrical energy storagecell (connected to an electrical connector) from electrical energystorage cells connected to the same electrical connector that have notfailed or are not failing. In another exemplary embodiment, a thresholdlevel of current would be an amount of electrical current (greater thanthe electrical current that flows through the bands under normaloperation conditions) that flows from a failed or failing electricalenergy storage cell connected to an electrical connector to otherelectrical energy storage cells that are not failing.

While not intending to be bound by any theory, it is believed that afactor that contributes to the instability and/or failure of a portableelectrical energy storage cell is the amount of thermal energy to whichthe portable electrical energy storage cell is exposed. The amount ofthermal energy the portable electrical energy cell is exposed to affectsthe temperature to which the portable electrical energy cell rises. Asthe temperature of the portable electrical energy storage cellincreases, the stability of the cell becomes less predictable and therisk of damage to internal or external components of the portableelectrical energy storage cell and/or the risk that the cell cathode mayreact with and decompose the electrolyte solution increases. Reaction ofthe cathode with the electrolyte provides another source of undesirablethermal energy and reactive gases, such as hydrocarbons. Under suchconditions, these gases may cause internal pressure within the cell toincrease and the temperature of the cell to increase further,potentially to a level that results in ignition of the cell electrolytein the presence of oxygen or an increase in the temperature of adjacentcells to undesirable levels.

When a portable electrical energy storage cell connected to anelectrical connector formed in accordance with embodiments describedherein fails, the electrical current flowing from the failing cell maycause the temperature of other portable electrical energy storage cellsconnected to the same electrical connector to increase. Alternatively,electrical energy from other non-failing portable electrical energystorage cells connected to the electrical connector to which the failingcell is attached may cause the temperature of those cells or the failingcell to increase. Such increases in the temperature of the non-failingor failing cells cause the cells to be less stable and more prone tofailure.

Embodiments in accordance with other aspects of the described subjectmatter include methods of manufacturing an electrical connector forelectrical connection to a plurality of portable electrical energystorage cells making up a portable electrical energy storage device.Electrical connectors in accordance with aspects of the disclosedembodiments are manufactured from electrically conductive materials,such as metals or metal alloys, including nickel or nickel alloys. In anexemplary embodiment, the electrical connectors are manufactured from anelectrically conductive substrate. The electrically conductive substrateis machined using metal working techniques to form the integralelectrically conductive tabs, integral electrically conductive supportsand integral electrically conductive bands. Examples of metal workingtechniques include bending, pressing, milling and cutting. Examples ofuseful cutting techniques include laser or plasma cutting and examplesof useful milling techniques include use of a computerized numericalcontrol (i.e., CNC) machining. Such techniques are used to form theplurality of integral electrically conductive tabs, plurality ofintegral electrically conductive supports, conductive bands and theelectrically conductive frame out of the electrically conductivesubstrate. In accordance with embodiments described herein, the cuttingor milling techniques are used to form one or more electricallyconductive bands in one of the plurality of electrically conductivesupports that extend from one of the integral electrically conductivetabs. Each of the electrically conductive bands has a cross-sectionalarea less than a cross-sectional area of another portion of the integralelectrically conductive support that extends from one of the integralelectrically conductive tabs. These electrically conductive bands can beformed numerous ways, including forming an opening or void that passesthrough the integral electrically conductive supports or by removingportions of an edge of the integral electrically conductive supports.Band formation is not limited to forming an opening or removing edges ofthe electrically conductive supports. The bands can be formed usingother techniques.

The bending or forming techniques may be used to shape the electricallyconductive substrate so that the electrically conductive tabs lie in aplane different from the plane in which the portion of the electricallyconductive substrate making up the electrically conductive frame lies.

In accordance with an exemplary described embodiment, an integralelectrically conductive tab is attached to a terminal of a portableelectrical energy storage cell using thermal fusing techniques (e.g.,spot welding or projection welding). Such techniques generate thermalenergy at the conductive tab, for example, via resistive heating. Thethermal energy causes the temperature of discrete locations within thetab to increase to a level where the integral electrically conductivetab thermally fuses (e.g., is welded) to a terminal of a portableelectrical energy storage cell in contact with the conductive tab. Thetemperature needed to thermally fuse the integral electricallyconductive tab to the portable electrical energy storage cell terminaldepends, in part, upon the composition of the integral electricallyconductive tab and the portable electrical energy storage cell terminal,the thickness of the conductive tab and target time for completing thethermal fusion. The thermal fusion process should be controlled so thetemperature of the tab and terminal are elevated just enough to createan effective attachment between the two, but not so high or for so longa time that damage to the electrical energy storage cell, including itsterminal, occurs, or is so high or maintained for such a long period oftime that unwanted chemical reactions within the cell are initiated.Practicing methods in accordance with embodiments described herein,utilizing electrical connectors of the type described herein, permitsreliable attachment of integral electrically conductive tabs to portableelectrical energy storage cell terminals. The electrical connectorsformed in accordance with embodiments described herein are able toelectrically isolate a failing or failed portable electrical energystorage cell from other cells connected to the same electricalconnector. Electrically isolating the failing or failed cell from othercells reduces the chances that the other cells will be damaged or willbecome unstable due to elevated temperatures.

An exemplary technique for attaching an integral electrically conductivetab to a terminal of an electrical energy storage cell includes spotwelding. A spot welder contacts electrodes with an electricallyconductive tab in at least two locations. An electric potential betweenthe electrodes causes an electric current to flow through the points ofcontact between the electrodes and the conductive tab. The small size ofthe contact area between the electrodes and the electrically conductivetab results in a large current flowing through the contact points. Theselarge currents cause a portion of the conductive tab to melt. Pressurefrom the electrodes promotes the fusion of the melted portion of theconductive tabs to the underlying terminal of an electrical energystorage cell. The foregoing detailed description has set forth variousembodiments of the devices via the use of schematic illustrations andexamples. Insofar as such schematics and examples contain one or morefunctions and/or operations, it will be understood by those skilled inthe art that each function and/or operation within such structures andexamples can be implemented, individually and/or collectively, by a widerange of hardware and combinations thereof. The various embodimentsdescribed above can be combined to provide further embodiments. All ofthe U.S. patents, U.S. patent application publications, U.S. patentapplications, foreign patents, foreign patent applications andnon-patent publications referred to in this specification and/or listedin the Application Data Sheet are incorporated herein by reference, intheir entirety. Aspects of the embodiments can be modified, ifnecessary, to employ concepts of the various patents, applications andpublications to provide yet further embodiments.

While generally discussed in the environment and context of powersystems for use with personal transportation vehicles such asall-electric scooters and/or motorbikes, the teachings herein can beapplied in a wide variety of other environments, including othervehicular as well as non-vehicular environments. Further, whileillustrated with reference to specific shapes and orientations, theillustrations and descriptions are not intended to be exhaustive or tolimit the embodiments to the precise forms illustrated. For example,electrical energy storage cells need not be round cylinders, but couldtake different shapes such as square cylinders, square boxes orrectangular boxes. Similarly, embodiments utilizing one electricalenergy storage cell module have been illustrated and described; however,such descriptions are not intended to be exhaustive or to limit theembodiments described herein to such precise configuration. For example,electrical energy storage cell modules may be placed side by side andseparated by the electrical energy storage cell barriers includinglayers of thermal insulating material and layers of elastic material.The above description of illustrated embodiments, including what isdescribed in the Abstract, is not intended to be exhaustive or to limitthe embodiments to the precise forms disclosed. Although specificembodiments and examples are described herein for illustrative purposes,various equivalent modifications can be made without departing from thespirit and scope of the disclosure, as will be recognized by thoseskilled in the relevant art.

In general, in the following claims, the terms used should not beconstrued to limit the claims to the specific embodiments disclosed inthe specification and the claims, but should be construed to include allpossible embodiments along with the full scope of equivalents to whichsuch claims are entitled. Accordingly, the claims are not limited by thedisclosure.

1. A method of manufacturing an electrical connector, comprising:providing an electrically conductive substrate; and forming a pluralityof integral electrically conductive tabs and a plurality of integralelectrically conductive supports in the electrically conductivesubstrate, one of the plurality of integral electrically conductivesupports extending from one of the integral electrically conductivetabs; wherein the one of the plurality of electrically conductivesupports extends from the one of the integral electrically conductivetabs, the one of the plurality of electrically conductive supportshaving a cross-sectional area less than a cross-sectional areasufficient to open an electrical connection between the one of theintegral electrically conductive tabs and the electrically conductivesubstrate if a current passing through the one of the plurality ofelectrically conductive supports exceeds a threshold level at which theone of the plurality of integral electrically conductive supports startsto fail.
 2. The method of claim 1, further comprising positioning theone of the plurality of the integral electrically conductive tabs in afirst plane parallel to a second plane in which the electricallyconductive substrate lies.
 3. The method of claim 1, further comprisingdisplacing the one of the plurality of the integral electricallyconductive tabs so it lies in a first plane different from a secondplane in which the electrically conductive substrate lies.
 4. The methodof claim 1, wherein the one of the plurality of electrically conductivesupports comprises an electrically conductive band having thecross-sectional area less than the cross-sectional area sufficient toopen the electrical connection, and wherein the electrically conductiveband is formed by removing a portion of the one of the plurality of theintegral electrically conductive supports extending from the one of theplurality of integral electrically conductive tabs.
 5. The method ofclaim 1, wherein the one of the plurality of electrically conductivesupports comprises an electrically conductive band having thecross-sectional area less than the cross-sectional area sufficient toopen the electrical connection, and wherein the electrically conductiveband comprises first and second electrically conductive band portionsextending from the one of the plurality of integral electricallyconductive tabs.
 6. The method of claim 5, wherein the firstelectrically conductive band portion has a first cross-sectional area,and wherein the second electrically conductive band portion has a secondcross-sectional area different from the first cross-sectional area. 7.The method of claim 5, wherein the first electrically conductive bandportion has a first cross-sectional area, and wherein the secondelectrically conductive band portion has a second cross-sectional areagenerally the same as the first cross-sectional area.
 8. The method ofclaim 1, wherein the one of the plurality of electrically conductivesupports comprises an electrically conductive band having thecross-sectional area less than the cross-sectional area sufficient toopen the electrical connection, and wherein the one of the plurality ofintegral electrically conductive supports is a first support, andwherein the one of the integral electrically conductive tabs is a firstconductive tab, and wherein the electrically conductive band is a firstelectrically conductive band, and wherein the method further comprisesforming a second electrically conductive band in a second support of theplurality of electrically conductive supports extending from a secondconductive tab of the plurality of the integral electrically conductivetabs.
 9. The method of claim 8, wherein the first electricallyconductive band has a first cross-sectional area, and wherein the secondelectrically conductive band has a second cross-sectional area generallythe same as the first cross-sectional area.
 10. The method of claim 8,wherein the first electrically conductive band has a firstcross-sectional area, and wherein the second electrically conductiveband has a second cross-sectional area different from the firstcross-sectional area.
 11. The method of claim 1, further comprisingforming the plurality of integral electrically conductive supports withsections having a constant width.
 12. The method of claim 1, wherein theone of the plurality of electrically conductive supports comprises anelectrically conductive band having the cross-sectional area less thanthe cross-sectional area sufficient to open the electrical connection,and wherein the electrically conductive band is formed by an openingpositioned in the one of the plurality of electrically conductivesupports.
 13. The method of claim 1, further comprising rotating the oneof the plurality of electrically conductive supports extending from theone of the integral electrically conductive tabs.
 14. A method ofconnecting a plurality of portable electrical energy storage cells of aportable electrical energy storage device, the method comprising:providing a plurality of integral electrically conductive tabs and aplurality of integral electrically conductive supports, wherein each ofthe plurality of integral electrically conductive supports extends froma corresponding one of the integral electrically conductive tabs, andwherein at least one of the integral electrically conductive supportsincludes an electrically conductive band having a cross-sectional arealess than a cross-sectional area threshold, and wherein thecross-sectional area threshold is indicative of a threshold current, andwherein the at least one conductive support starts to fail if thethreshold current passes through the at least one conductive support;heating at least one of the integral electrically conductive tabs; andthermally fusing the heated at least one integral electricallyconductive tab to one of the plurality of portable electrical energystorage cells.
 15. The method of claim 14, further comprisingpositioning the at least one of the integral electrically conductivetabs in a first plane parallel to a second plane of an electricallyconductive frame.
 16. The method of claim 14, further comprisingdisplacing the at least one of the plurality of the integralelectrically conductive tabs so it lies in a first plane different froma second plane of an electrically conductive frame.
 17. The method ofclaim 14, wherein the electrically conductive band is formed by formingan opening in the at least one of the integral electrically conductivesupports.
 18. A method of manufacturing an electrical connector,comprising: forming an integral electrically conductive support in anelectrically conductive frame; forming an integral electricallyconductive tab extending from the integral electrically conductivesupport; and forming an electrically conductive band between theintegral electrically conductive support and the integral electricallyconductive tab by forming an opening in the integral electricallyconductive support, the electrically conductive band having across-sectional area less than a cross-sectional area sufficient to openan electrical connection between the integral electrically conductivetab and the electrically conductive frame if a current passing throughthe electrically conductive band exceeds a threshold level at which theintegral electrically conductive support starts to fail.
 19. The methodof claim 18, wherein forming the electrically conductive band comprisesforming first and second electrically conductive band portionssurrounding the opening.
 20. The method of claim 19, wherein the firstelectrically conductive band portion has a first cross-sectional area,and wherein the second electrically conductive band portion has a secondcross-sectional area generally the same as the first cross-sectionalarea.